Wildlife Policies Making Populations Unstable, Study Finds

Wildlife resource managers should rethink policies for the sustainable harvesting of fish and wildlife populations, according to new research by a University of Guelph professor.

In a paper published today in Science, integrative biology professor John Fryxell says current ad hoc management practices make fish and wildlife populations unstable and more vulnerable to extinction.

For the study, Fryxell, along with Guelph ecologist Kevin McCann and scholars from the United States and Norway, developed a model based on assumptions about human collective behaviour and current hunting and fishing regulations. They tested it using data from three populations of hunted ungulates from Canada and Norway over a 20-year period.

Currently, there is an “open access” philosophy when it comes to fishing and hunting, meaning there is little government restriction other than maximum quotas on harvests, Fryxell said.

“Quotas tend to change very slowly from year to year, largely based on the success of hunters and anglers in previous years more than anything else,” he said.

The number of hunters in a given year is determined by the social sharing of information.

“When some recreational hunters are successful, this naturally encourages other hunters to jump in,” Fryxell said. “As long as there are lots of animals to hunt, this is fine. The problem is that it takes time for the pool of hunters to build up or decline in response to changes in wildlife or fish populations that they are pursuing.”

The delayed response by both managers and recreational hunters creates a cycle of abundance in the wildlife populations.

“A social dynamic is driving wildlife populations up and down; nothing is there to maintain a constant fraction of harvested animals.”

This causes a significant fluctuation in resources and volatile populations, the researchers found.

This could be problematic if wildlife face other challenges, Fryxell said.

“Bad things can happen if over harvesting coincides with a rough winter or a disease outbreak — you risk serious population collapse.”

It can take decades for large animal populations to recover from such collapses.

“Sadly, we know this all too well from our disastrous experience with cod stocks off the coast of Newfoundland,” Fryxell said.

Current practices of open access combined with minor yearly adjustments in quotas are insufficient for long-term protection.

“It’s like a person who decides they need to lose weight and thinking that they can do it by cutting out a doughnut here or there or by having one less glass of wine,” Fryxell said. “It’s not going to do the trick; you need to make more strategic long-term changes to make a difference.”

He added that the open access and quota system has endured for many reasons, including prevailing philosophies about natural resources and public use and the fact that changes in wildlife populations happen gradually “so we are oblivious to patterns of slow collapse.”

“But now that we know what can happen, we should step back and look at a variety of ways to set up much more stable regimes,” Fryxell said.

One solution is having wildlife managers work to ensure a more constant level of hunting effort from one year to the next. When populations are at a low point, hunting caps would result in far fewer animals being harvested. Conversely, many more animals could be safely harvested during population peaks, he said.

“We will have to change the way we manage wild populations of animals and accept that hunters cannot be free to come and go as they please. The level of hunting and fishing must match the wildlife resources available.”